<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <input type="button" value="toggle" @click="flag =! flag" />
        <h3 v-if="flag">这是一个h3标签</h3>
    </div>
    <script src="../../js/vue.js"></script>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                flag: false
            },
        });
    </script>
</body>
</html>